The Cape Town high court ordered the son of the former prime minister to pay a 300,000 fine and gave him a four-year suspended prison sentence.
Judge Abe Motala warned Thatcher that if he does not pay the fine he will face a five-year prison sentence with a further four years suspended for five years.
Thatcher admitted to paying for a military helicopter used by the mercenaries in the failed plot but maintained that he believed it was to used as an air ambulance, lying bastard.
The helicopter's pilot, Crause Steyl, had told the South African authorities that its purpose was to provide air support for the military overthrow of Equatorial Guinea's president, Teodoro Obiang.
The coup plot was led by one of Thatcher's former neighbours in Cape Town, the former SAS officer and mercenary Simon Mann, who is serving a seven-year jail sentence in Zimbabwe for his part in the conspiracy.
Last night a spokesman for Lady Thatcher said: "She is very relieved that matters have now been settled and that the worry of these last few months is now over." However she is going senile, and probably hasn't a clue what day it is. (see health watch)Health Watch Arriving at court this morning, Thatcher refused to answer journalists' questions and ignored a poster hung in a window across the street reading "Save me mummy".